10. High Spinal

Question 1

What is a high spinal

Answer 1

Spinal anaesthesia is commonly administered
to provide dense peri-operative analgesia
for surgical procedures involving the abdomen or lower limbs.

The spread of intrathecal local anaesthetic above T4 constitutes high spinal anaesthesia.

Total spinal may be defined as intrathecal local anaesthetic-induced depression of the cervical spinal cord and/or brainstem.

It may occur secondary to administration of an excessive dose of local anaesthetic or excessive spread of a correct dose.

Question 2

What factors determine the intrathecal spread of local

anaesthetic?

Answer 2

1. > L ocal anaesthetic:
   dosage, volume and baricity
2. > Patient position
3. > Patient characteristics,
   e.g. height, intra-abdominal pressure

4.
> Injection technique,
e.g. speed of injection, barbotage
(i.e. repeated injection and aspiration of the fluid)

Question 3

What are the clinical features of high spinal blockade?

Answer 3

Clinical features are determined by the height of the block:

1.
> Cardiovascular:
• Hypotension due to vasodilatation
• Bradycardia may occur due to inhibition of 
cardio-accelerator fibres
(T1–T4).

2.
> Respiratory:
• Intercostal muscle paralysis leading
to reduced tidal volumes

• Block above C3 will involve the diaphragm
and may cause respiratory embarrassment

• Total spinal will involve the brainstem and result in apnoea

3. > Neurological:
   • Total spinal anaesthesia will result in loss of consciousness.
4. > Sensory loss:
   • Paraesthesia in the upper limbs may progress into the face.

5.
> Motor loss:
• Motor loss in the upper limbs
indicates high spinal blockade.

Question 4

How would you manage a high spinal anaesthetic block?

Answer 4

A rapidly ascending block may present as cardio-respiratory arrest.

State that this is an anaesthetic emergency
and that you would call for senior anaesthetic assistance.

• Adopt an ABC approach. Management is supportive.
• Administer 100% O2.

• Monitor adequacy of breathing –
consider intubation and ventilation.

• Support the circulation – administration of fluid plus vasopressors, e.g. phenylephrine.
• Treat bradycardia, e.g. atropine/ephedrine.
• Support ventilation and circulation until block has regressed.
• Document the event in the medical notes and complete a critical incident report.
• Inform the patient of the event.